A Hong Kong rights group has accused supplier Biel Crystal of mistreating workers who are making touchscreens for Apple, Samsung and other smartphone makers.

The Students & Scholars Against Corporate Misbehaviour (SACOM) released a report which claimed that Biel was forcing employees to work 11-hour shifts, seven days a week with only one day off every month.

The report said that at least five suicides had taken place at the factory since 2011, as workers were subjected to "military-style management", frequent injuries, delayed wages and other violations of their rights.

Apple said in an emailed statement that it cared about all its workers and would continue to inspect supplier factories.

"We insist that our suppliers provide safe working conditions, treat workers with dignity and respect, and use environmentally responsible manufacturing processes wherever Apple products are made," the firm said. "Our suppliers must live up to these requirements if they want to keep doing business with Apple.

"Every year Apple inspects more factories, going deeper into the supply chain and raising the bar for our suppliers. In 2012 we conducted 393 audits at supplier facilities around the world and reported their progress on apple.com."

According to the report, Biel Crystal supplies 60 per cent of the world's touchscreen glass from its factories in Shenzhen and Huizhou to mobile firms like HTC, Nokia, LG and Motorola. The company supplies 60 per cent of the glass for Apple iDevices and 20 per cent of Samsung products, SACOM said. It also supplies glass to watchmakers in Europe, which was how the business started before mobes came along.

SACOM said that the factories have an annual revenue of 30bn yuan ($4.9bn) and employ 80,000 workers. ®